Originally Posted by 230lx434

Will be having motor dynoed shortly but will not have the Stainless Marine manifolds nor extended riders strapped on for dyno session. How much will it affect the tune once motor is back in boat? I have contemplated buying and using a set of midlength 1 5/8ths primary x 3" collector headers as the shorter primary length to collector distances seems reasonable to what the manifold/riser will be. Any suggestions on the best way of going about this would be greatly appreciated!